Published German patent application DE-OS No. 34 16 495 discloses a position transmitter embodied as a potentiometer in which switching functions are triggered in correspondence with the potentiometer position. For the purpose of very precise correspondence of the switching functions with the potentiometer position, electrical switches having spatially defined ON and OFF switching points are arranged on the one potentiometer board carrying the collector path. The ON and OFF switching points are defined with respect to this collector path. Each switch includes a contact path and a contact finger rotating over and sliding on the corresponding contact path, the contact finger being mechanically connected to the potentiometer member. The beginning and end of the contact paths determine the ON and OFF point of each switch. In mass-produced products, the high production cost of the necessary mechanical precision parts such as contact paths, contact fingers and the like is disadvantageous.
A reproducible correspondence of the triggering of the switching function with a particular potentiometer circuit can be insured only by means of a low manufacturing tolerance of the potentiometer used as the position transmitter. A disadvantage is the unavoidable long-term drift of this correspondence caused by environmental factors and by aging of the position transmitter.